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Chocolate and Blood Pressure

Jacob Schor, ND, FABNO

Park Hill News

April 2010

 

Things that taste good are typically not good for you.  Chocolate is the exception to this rule.  Scientist keep revealing one after another condition for which chocolate is good for you.  A particularly interesting benefit appears to be in the prevention and even possibly treatment of high blood pressure. 

The discovery that chocolate lowers blood pressure comes from an unexpected quarter, the Kuna Indians of Panama.  Most of the Kuna live on islands off the eastern coast of Panama.  They’ve lived there pretty much isolated from the rest of the world since the time of the Spanish conquistadors.  In the 1940s, medical researchers noticed and reported that the Kuna don’t get high blood pressure as they get older.  This is rather striking as it is assumed that everyone’s blood pressure increases with age.  Just a few years ago Harvard researchers looked more closely at the Kuna assuming this blood pressure protection was genetic.   To everyone’s surprise the Kuna’s stable blood pressures are not genetic; the Kuna only had low blood pressure when they lived on the islands.  If they move to Panama City, their blood pressures shoot up. 

Looking for other explanations the Harvard researchers carefully surveyed the Kuna diet looking for difference between the island dwelling and city living tribe members.  As expected those spending their lives on the sea ate more fish.  What was not easy to predict were the huge quantities of cocoa the island dwellers drank.  The island dwelling Kuna, much as their ancestors have, make a beverage from cacao beans and this was pretty much the only liquid they consumed, drinking neither coffee, tea soda or even water, they drink about five or more cups a day of their cocoa brew.

As surprising as this seemed at first, in hindsight it wasn’t.  Earlier studies, many sponsored by the Mars Candy Company had already determined that specific flavanols in chocolate convey health benefits.  In fact Mars has for years been working to increase the amount of these particular chemicals in their chocolates.  The Kuna consume enough chocolate flavanols in their diet to trigger production of enzymes called nitric oxide synthases.  These enzymes convert the amino acid l-arginine into nitric oxide, which causes blood vessel dilation.  You may recognize the term nitric oxide; Viagra increases nitric oxide in one particular area.  In general though, nitric oxide lowers blood pressure.

This chocolate action is gaining support in the science literature.  Last year, Stefan Desch and colleagues in Germany completed a meta-analysis of chocolate hypertension studies, analyzing data from ten separate published clinical trials. In their analysis chocolate, decreased systolic blood pressure an average of almost 5 points and diastolic by almost 3.

Chocolate protects against heart disease in other ways besides lowering blood pressure.  It decreases vascular inflammation and it also improves cholesterol risk factors.  A 2008 study reported that a 700 mg per day of chocolate flavanols caused impressive changes in blood lipids in their study participants.  After just one week, low-density lipoprotein fell by 6% and high-density lipoprotein rose by 9%.  It also reduced c-reactive protein levels. 

As good as all of this information sounds, don’t rush out to buy chocolate just yet.  Most chocolate sold in the United States is highly processed; the heat used during manufacture destroys most of the flavanols.  Thus we cannot expect your average bar to have significant effects on blood pressure.  If you want to lower your blood pressure by eating chocolate you need to eat one of the high flavanol chocolates.  The published studies use chocolates that provide 500 to 1,000 mg of flavanol per day. These are approximately the amount of flavanols the Kuna are estimated to consume each day.

 And that’s a problem because few chocolates are made in such a way as to preserve flavanols.  Hershey’s Special Dark Cocoa has 60 mg of flavanol in 1 tbsp (5 g). the ‘Kuna dose’ of flavanol would take 8 to 16 TB of cocoa powder.  That’s a bit too much of a ‘good thing’ for most of us to eat in a day.

Two companies have pioneered the development of high flavanol chocolates; the Mars company here in the U.S., and Barry Callebaut in Belgium.  Both have spent years selecting and breeding cacao beans to increase flavanol content and refining their processing technology to preserve flavanol in the finished chocolates.  The two companies have recently teamed up in a joint venture to sell Callebaut’s high flavanol chocolates to American manufacturers.  Callebaut currently sells a cocoa powder in Europe that contains 100 mg of flavanol per gram.  One Tablespoon of their cocoa powder supplies 500 mg of flavanol; that is the kind of dose most of could eat happily.

In the coming months you may be able to grab a chocolate bar while standing in the check-out line and be able to honestly say, “This is good for me.”